From fdcdad42ff96fea3c05598e378d3c44ad4a51bde Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Iiro=20J=C3=A4ppinen?= <iiro@jappinen.fi>
Date: Thu, 1 Feb 2024 20:59:39 +0200
Subject: [PATCH] fix: do not try to load configuration from files that are not
 checked out

---
 .changeset/wet-cups-jog.md      |  5 +++++
 lib/searchConfigs.js            | 23 ++++++++++++++---------
 test/unit/searchConfigs.spec.js | 20 +++++++++++++++++++-
 3 files changed, 38 insertions(+), 10 deletions(-)
 create mode 100644 .changeset/wet-cups-jog.md

diff --git a/.changeset/wet-cups-jog.md b/.changeset/wet-cups-jog.md
new file mode 100644
index 000000000..2877ed111
--- /dev/null
+++ b/.changeset/wet-cups-jog.md
@@ -0,0 +1,5 @@
+---
+'lint-staged': patch
+---
+
+_Lint-staged_ no longer tries to load configuration from files that are not checked out. This might happen when using sparse-checkout.
diff --git a/lib/searchConfigs.js b/lib/searchConfigs.js
index ba878c01e..deee7ad10 100644
--- a/lib/searchConfigs.js
+++ b/lib/searchConfigs.js
@@ -13,10 +13,9 @@ import { CONFIG_FILE_NAMES } from './configFiles.js'
 
 const debugLog = debug('lint-staged:searchConfigs')
 
-const EXEC_GIT = ['ls-files', '-z', '--full-name']
+const EXEC_GIT = ['ls-files', '-z', '--full-name', '-t']
 
-const filterPossibleConfigFiles = (files) =>
-  files.filter((file) => CONFIG_FILE_NAMES.includes(path.basename(file)))
+const filterPossibleConfigFiles = (file) => CONFIG_FILE_NAMES.includes(path.basename(file))
 
 const numberOfLevels = (file) => file.split('/').length
 
@@ -58,17 +57,23 @@ export const searchConfigs = async (
     return { [configPath]: validateConfig(config, filepath, logger) }
   }
 
-  const [cachedFiles, otherFiles] = await Promise.all([
+  const [cachedFilesWithStatus, otherFilesWithStatus] = await Promise.all([
     /** Get all possible config files known to git */
-    execGit(EXEC_GIT, { cwd: gitDir }).then(parseGitZOutput).then(filterPossibleConfigFiles),
+    execGit(EXEC_GIT, { cwd: gitDir }).then(parseGitZOutput),
     /** Get all possible config files from uncommitted files */
-    execGit([...EXEC_GIT, '--others', '--exclude-standard'], { cwd: gitDir })
-      .then(parseGitZOutput)
-      .then(filterPossibleConfigFiles),
+    execGit([...EXEC_GIT, '--others', '--exclude-standard'], { cwd: gitDir }).then(parseGitZOutput),
   ])
 
   /** Sort possible config files so that deepest is first */
-  const possibleConfigFiles = [...cachedFiles, ...otherFiles]
+  const possibleConfigFiles = [...cachedFilesWithStatus, ...otherFilesWithStatus]
+    .flatMap(
+      /**
+       * Leave out lines starting with "S " to ignore not-checked-out files in a sparse repo.
+       * The "S" status means a tracked file that is "skip-worktree"
+       * @see https://git-scm.com/docs/git-ls-files#Documentation/git-ls-files.txt--t
+       */ (line) => (line.startsWith('S ') ? [] : [line.replace(/^[HSMRCK?U] /, '')])
+    )
+    .filter(filterPossibleConfigFiles)
     .map((file) => normalizePath(path.join(gitDir, file)))
     .filter(isInsideDirectory(cwd))
     .sort(sortDeepestParth)
diff --git a/test/unit/searchConfigs.spec.js b/test/unit/searchConfigs.spec.js
index fcc156831..5a6d7eaa1 100644
--- a/test/unit/searchConfigs.spec.js
+++ b/test/unit/searchConfigs.spec.js
@@ -101,7 +101,7 @@ describe('searchConfigs', () => {
     const config = { '*.js': 'eslint' }
 
     execGit.mockResolvedValueOnce(
-      `.lintstagedrc.json\u0000even/deeper/.lintstagedrc.json\u0000deeper/.lintstagedrc.json\u0000`
+      `H .lintstagedrc.json\u0000H even/deeper/.lintstagedrc.json\u0000H deeper/.lintstagedrc.json\u0000`
     )
 
     const topLevelConfig = normalizePath(path.join(process.cwd(), '.lintstagedrc.json'))
@@ -118,4 +118,22 @@ describe('searchConfigs', () => {
 
     expect(Object.keys(configs)).toEqual([evenDeeperConfig, deeperConfig, topLevelConfig])
   })
+
+  it('should ignore config files skipped from the worktree (sparse checkout)', async () => {
+    const config = { '*.js': 'eslint' }
+
+    execGit.mockResolvedValueOnce(`H .lintstagedrc.json\u0000S skipped/.lintstagedrc.json\u0000`)
+
+    const topLevelConfig = normalizePath(path.join(process.cwd(), '.lintstagedrc.json'))
+    const skippedConfig = normalizePath(path.join(process.cwd(), 'skipped/.lintstagedrc.json'))
+
+    loadConfig.mockResolvedValueOnce({ config, filepath: topLevelConfig })
+
+    // Mock will return config for skipped file, but it should not be read
+    loadConfig.mockResolvedValueOnce({ config, filepath: skippedConfig })
+
+    const configs = await searchConfigs({})
+
+    expect(Object.keys(configs)).toEqual([topLevelConfig])
+  })
 })